U.S. patent number 7,828,690 [Application Number 12/397,551] was granted by the patent office on 2010-11-09 for ten-speed transmissions.
This patent grant is currently assigned to GM Global Technology Operations, Inc.. Invention is credited to Clinton E. Carey, James M. Hart, Andrew W. Phillips, Scott H. Wittkopp.
United States Patent |
7,828,690 |
Wittkopp , et al. |
November 9, 2010 |
Ten-speed transmissions
Abstract
The transmission has a plurality of members that can be utilized
in powertrains to provide at least ten forward speed ratios and one
reverse speed ratio. The transmission includes four planetary gear
sets, six torque-transmitting devices, and two fixed
interconnections. The powertrain includes an engine and torque
converter that is continuously connected to one of the planetary
gear members and an output member that is continuously connected
with another one of the planetary gear members. The six
torque-transmitting devices provide interconnections between
various gear members and the transmission housing, and are operated
in combinations of three to establish at least ten forward speed
ratios and one reverse speed ratio.
Inventors: |
Wittkopp; Scott H. (Ypsilanti,
MI), Phillips; Andrew W. (Rochester, MI), Hart; James
M. (Belleville, MI), Carey; Clinton E. (Highland,
MI) |
Assignee: |
GM Global Technology Operations,
Inc. (Detroit, MI)
|
Family
ID: |
42664240 |
Appl.
No.: |
12/397,551 |
Filed: |
March 4, 2009 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20100227729 A1 |
Sep 9, 2010 |
|
Current U.S.
Class: |
475/280;
475/288 |
Current CPC
Class: |
F16H
3/66 (20130101); F16H 2200/0069 (20130101); F16H
2200/2046 (20130101); F16H 2200/2012 (20130101) |
Current International
Class: |
F16H
3/44 (20060101) |
Field of
Search: |
;475/271,275-291 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Le; David D
Assistant Examiner: Knight; Derek D
Attorney, Agent or Firm: Quinn Law Group, PLLC
Claims
The invention claimed is:
1. A multi-speed transmission comprising: an input member; an
output member; first, second, third and fourth planetary gear sets
each having first, second and third members; a first
interconnecting member continuously connecting said first member of
said first planetary gear set with one of said second and said
third member of said second planetary gear set and with said third
member of said third planetary gear set; a second interconnecting
member continuously connecting said second member of said first
planetary gear set with said first member of said second planetary
gear set and with said first or said second member of said third
planetary gear set if said first interconnecting member
continuously connects said first member of said first planetary
gear set with said second member of said second planetary gear set,
or continuously connecting said second member of said first
planetary gear set with said first or said second member of said
second planetary gear set and with said first or said second member
of said third planetary gear set if said first interconnecting
member continuously connects said first member of said first
planetary gear set with said third member of said second planetary
gear set; and six torque-transmitting devices being engaged in
combinations of three to establish at least ten forward speed
ratios and at least one reverse speed ratio between said input
member and said output member.
2. The transmission of claim 1, wherein a first of said six
torque-transmitting devices selectively connects said first member
of said first planetary gear set or said second member of said
third planetary gear set with a stationary member.
3. The transmission of claim 2, wherein a second of said six
torque-transmitting devices selectively connects said first or said
third member of said fourth planetary gear set with said stationary
member.
4. The transmission of claim 3, wherein a third of said six
torque-transmitting devices selectively connects said first member
of said fourth planetary gear set with said stationary member; or
said third of said six torque-transmitting devices selectively
connects said second member of said first planetary gear set with
said third member of said fourth planetary gear set.
5. The transmission of claim 4, wherein a fourth of said six
torque-transmitting devices selectively connects said first or said
second member of said first planetary gear set with said first or
said second member of said fourth planetary gear set.
6. The transmission of claim 5, wherein a fifth of said six
torque-transmitting devices selectively connects said first member
of said first planetary gear set or said third member of said
second planetary gear set with said second or said third member of
said fourth planetary gear set.
7. The transmission of claim 6, wherein a sixth of said six
torque-transmitting devices selectively connects said first member
of said second or said third planetary gear set with said first or
said third member of said fourth planetary gear set.
8. The transmission of claim 7, wherein said input member is
continuously connected with said third member of said first
planetary gear set; and said output member is continuously
connected with said second member of said fourth planetary gear
set.
9. The transmission of claim 8, wherein said first, second and
third members of said first, second, third and fourth planetary
gear sets comprise a sun gear member, a planet carrier assembly
member and a ring gear member, respectively.
10. The transmission of claim 1, wherein said input member is
continuously connected with said third member of said first
planetary gear set; said output member is continuously connected
with said second member of said fourth planetary gear set; said
first interconnecting member continuously connects said first
member of said first planetary gear set with said third member of
said second planetary gear set and with said third member of said
third planetary gear set; said second interconnecting member
continuously connects said second member of said first planetary
gear set with said second member of said second planetary gear set
and with said first member of said third planetary gear set; said
first torque-transmitting device selectively connects said second
member of said third planetary gear set with said stationary
member; said second torque-transmitting device selectively connects
said first member of said fourth planetary gear set with said
stationary member; said third torque-transmitting device
selectively connects said second member of said first planetary
gear set with said third member of said fourth planetary gear set;
said fourth torque-transmitting device selectively connects said
first member of said first planetary gear set with said first
member of said fourth planetary gear set; said fifth
torque-transmitting device selectively connects said first member
of said first planetary gear set with said second member of said
fourth planetary gear set; and said sixth torque-transmitting
device selectively connects said first member of said second
planetary gear set with said third member of said fourth planetary
gear set wherein said first, second and third members of said
first, second, third, and fourth planetary gear sets comprise a sun
gear member, a planet carrier assembly member and a ring gear
member, respectively.
11. The transmission of claim 1, wherein said input member is
continuously connected with said third member of said first
planetary gear set; said output member is continuously connected
with said second member of said fourth planetary gear set; said
first interconnecting member continuously connects said first
member of said first planetary gear set with said second member of
said second planetary gear set and with said third member of said
third planetary gear set; said second interconnecting member
continuously connects said second member of said first planetary
gear set with said first member of said second planetary gear set
and with said second member of said third planetary gear set; said
first torque-transmitting device selectively connects said first
member of said first planetary gear set with said stationary
member; said second torque-transmitting device selectively connects
said third member of said fourth planetary gear set with said
stationary member; said third torque-transmitting device
selectively connects said first member of said fourth planetary
gear set with said stationary member; said fourth
torque-transmitting device selectively connects said second member
of said first planetary gear set with said second member of said
fourth planetary gear set; said fifth torque-transmitting device
selectively connects said third member of said second planetary
gear set with said third member of said fourth planetary gear set;
and said sixth torque-transmitting device selectively connects said
first member of said third planetary gear set with said first
member of said fourth planetary gear set wherein said first, second
and third members of said first, second, third, and fourth
planetary gear sets comprise a sun gear member, a planet carrier
assembly member and a ring gear member, respectively.
12. A multi-speed transmission comprising: an input member; an
output member; first, second, third and fourth planetary gear sets
each having first, second and third members; a first
interconnecting member continuously connecting said first member of
said first planetary gear set with said third member of said second
planetary gear set and with said third member of said third
planetary gear set; a second interconnecting member continuously
connecting said second member of said first planetary gear set with
said second member of said second planetary gear set and with said
first member of said third planetary gear set; a first
torque-transmitting device selectively connecting said second
member of said third planetary gear set with a stationary member; a
second torque-transmitting device selectively connecting said first
member of said fourth planetary gear set with said stationary
member; a third torque-transmitting device selectively connecting
said second member of said first planetary gear set with said third
member of said fourth planetary gear set; a fourth
torque-transmitting device selectively connecting said first member
of said first planetary gear set with said first member of said
fourth planetary gear set; a fifth torque-transmitting device
selectively connecting said first member of said first planetary
gear set with said second member of said fourth planetary gear set;
a sixth torque-transmitting device selectively connecting said
first member of said second planetary gear set with said first or
said third member of said fourth planetary gear set; and said six
torque-transmitting devices being engaged in combinations of three
to establish at least ten forward speed ratios and at least one
reverse speed ratio between said input member and said output
member.
13. A multi-speed transmission comprising: an input member; an
output member; first, second, third and fourth planetary gear sets
each having first, second and third members; a first
interconnecting member continuously connecting said first member of
said first planetary gear set with said second member of said
second planetary gear set and with said third member of said third
planetary gear set; a second interconnecting member continuously
connecting said second member of said first planetary gear set with
said first member of said second planetary gear set and with said
second member of said third planetary gear set; a first
torque-transmitting device selectively connecting said first member
of said first planetary gear set with a stationary member; a second
torque-transmitting device selectively connecting said third member
of said fourth planetary gear set with said stationary member; a
third torque-transmitting device selectively connecting said first
member of said fourth planetary gear set with said stationary
member; a fourth torque-transmitting device selectively connecting
said second member of said first planetary gear set with said
second member of said fourth planetary gear set; a fifth
torque-transmitting device selectively connecting said third member
of said second planetary gear set with said third member of said
fourth planetary gear set; a sixth torque-transmitting device
selectively connecting said first member of said third planetary
gear set with said first member of said fourth planetary gear set;
and said six torque-transmitting devices being engaged in
combinations of three to establish at least ten forward speed
ratios and at least one reverse speed ratio between said input
member and said output member.
Description
TECHNICAL FIELD
The present invention relates to a power transmission having four
planetary gear sets that are controlled by six torque-transmitting
devices to provide at least ten forward speed ratios and one
reverse speed ratio.
BACKGROUND OF THE INVENTION
Passenger vehicles include a powertrain that is comprised of an
engine, multi-speed transmission, and a differential or final
drive. The multi-speed transmission increases the overall operating
range of the vehicle by permitting the engine to operate through
its torque range a number of times. The number of forward speed
ratios that are available in the transmission determines the number
of times the engine torque range is repeated. Early automatic
transmissions had two speed ranges. This severely limited the
overall speed range of the vehicle and therefore required a
relatively large engine that could produce a wide speed and torque
range. This resulted in the engine operating at a specific fuel
consumption point during cruising, other than the most efficient
point. Therefore, manually-shifted (countershaft transmissions)
were the most popular.
With the advent of three- and four-speed automatic transmissions,
the automatic shifting (planetary gear) transmission increased in
popularity with the motoring public. These transmissions improved
the operating performance and fuel economy of the vehicle. The
increased number of speed ratios reduces the step size between
ratios and therefore improves the shift quality of the transmission
by making the ratio interchanges substantially imperceptible to the
operator under normal vehicle acceleration.
Six-speed transmissions offer several advantages over four- and
five-speed transmissions, including improved vehicle acceleration
and improved fuel economy. While many trucks employ power
transmissions having six or more forward speed ratios, passenger
cars are still manufactured with three- and four-speed automatic
transmissions and relatively few five- or six-speed devices due to
the size and complexity of these transmissions.
Seven-, eight-, nine- and ten-speed transmissions provide further
improvements in acceleration and fuel economy over six-speed
transmissions. However, like the six-speed transmissions discussed
above, the development of seven-, eight-, nine- and ten-speed
transmissions has been precluded because of complexity, size and
cost.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved
transmission having four planetary gear sets controlled to provide
at least ten forward speed ratios and one reverse speed ratio.
The transmission family of the present invention has four planetary
gear sets, each of which includes a first, second and third member,
which members may comprise a sun gear, a ring gear, or a planet
carrier assembly member, in any order.
In referring to the first, second, third and fourth gear sets in
this description and in the claims, these sets may be counted
"first" to "fourth" in any order in the drawing (i.e., left to
right, right to left, etc.). Additionally, the first, second or
third members of each gear set may be counted "first" to "third" in
any order in the drawing (i.e., top to bottom, bottom to top, etc.)
for each gear set.
Each carrier member can be either a single-pinion carrier member
(simple) or a double-pinion carrier member (compound). Embodiments
with long pinions are also possible.
The input member is continuously connected with the third member of
the first or second planetary gear set. The output member is
continuously connected with the second member of the fourth
planetary gear set.
A first interconnecting member continuously connects the first
member of the first planetary gear set with the second or third
member of the second planetary gear set and with the third member
of the third planetary gear set.
A second interconnecting member continuously connects the second
member of the first planetary gear set with the first or second
member of the second planetary gear set and with the first or
second member of the third planetary gear set.
A first torque-transmitting device, such as a brake, selectively
connects the first member of the first planetary gear set or the
second member of the third planetary gear set with a stationary
member (transmission housing/casing).
A second torque-transmitting device, such as a brake, selectively
connects the first or third member of the fourth planetary gear set
with a stationary member (transmission housing/casing).
A third torque-transmitting device, such as a brake, selectively
connects the first member of the fourth planetary gear set with a
stationary member (transmission housing/casing). Alternatively, a
third torque-transmitting device, such as a clutch, selectively
connects the second member of the first planetary gear set with the
third member of the fourth planetary gear set.
A fourth torque-transmitting device, such as a clutch, selectively
connects the first or second member of the first planetary gear set
with the first or second member of the fourth planetary gear
set.
A fifth torque-transmitting device, such as a clutch, selectively
connects the first member of the first planetary gear set or the
third member of the second planetary gear set with the second or
third member of the fourth planetary gear set.
A sixth torque-transmitting device, such as a clutch, selectively
connects the first member of the second or third planetary gear set
with the first or third member of the fourth planetary gear
set.
The six torque-transmitting devices are selectively engageable in
combinations of three to yield at least ten forward speed ratios
and one reverse speed ratio.
A variety of speed ratios and ratio spreads can be realized by
suitably selecting the tooth ratios of the planetary gear sets.
The above features and other features and advantages of the present
invention are readily apparent from the following detailed
description of the best modes for carrying out the invention when
taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1a is a schematic representation of a powertrain including a
planetary transmission in accordance with the present
invention;
FIG. 1b is a truth table and chart depicting some of the operating
characteristics of the powertrain shown in FIG. 1a;
FIG. 1c is a schematic representation of the powertrain of FIG. 1a
depicted in lever diagram form;
FIG. 2a is a schematic representation of a powertrain including a
planetary transmission incorporating another family member of the
present invention;
FIG. 2b is a truth table and chart depicting some of the operating
characteristics of the powertrain shown in FIG. 2a; and
FIG. 2c is a schematic representation of the powertrain of FIG. 2a
depicted in lever diagram form.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, there is shown in FIG. 1a a powertrain
10 having a conventional engine and torque converter 12, a
planetary transmission 14, and a conventional final drive mechanism
16. The engine 12 may be powered using various types of fuel to
improve the efficiency and fuel economy of a particular
application. Such fuels may include, for example, gasoline; diesel;
ethanol; dimethyl ether; etc.
The planetary transmission 14 includes an input member 17
continuously connected with the engine 12, a planetary gear
arrangement 18, and an output member 19 continuously connected with
the final drive mechanism 16. The planetary gear arrangement 18
includes four planetary gear sets 20, 30, 40 and 50.
The planetary gear set 20 includes a sun gear member 22, a ring
gear member 24, and a planet carrier assembly member 26. The planet
carrier assembly member 26 includes a plurality of pinion gears 27
rotatably mounted on a carrier member 29 and disposed in meshing
relationship with both the sun gear member 22 and the ring gear
member 24.
The planetary gear set 30 includes a sun gear member 32, a ring
gear member 34, and a planet carrier assembly member 36. The planet
carrier assembly member 36 includes a plurality of pinion gears 37
rotatably mounted on a carrier member 39 and disposed in meshing
relationship with both the sun gear member 32 and the ring gear
member 34.
The planetary gear set 40 includes a sun gear member 42, a ring
gear member 44, and a planet carrier assembly member 46. The planet
carrier assembly member 46 includes a plurality of pinion gears 47
mounted on a carrier member 49 and disposed in meshing relationship
with both the ring gear member 44 and the sun gear member 42.
The planetary gear set 50 includes a sun gear member 52, a ring
gear member 54, and a planet carrier assembly member 56. The planet
carrier assembly member 56 includes a plurality of pinion gears 57
mounted on a carrier member 59 and disposed in meshing relationship
with both the ring gear member 54 and the sun gear member 52.
The planetary gear arrangement also includes six
torque-transmitting devices 80, 82, 84, 85, 86 and 87. The
torque-transmitting devices 80 and 82 are stationary-type
torque-transmitting devices, commonly termed brakes or reaction
clutches. The torque-transmitting devices 84, 85, 86 and 87 are
rotating-type torque-transmitting devices, commonly termed
clutches.
The input member 17 is continuously connected with the ring gear
member 24 of the planetary gear set 20. The output member 19 is
continuously connected with the planet carrier assembly member 56
of the planetary gear set 50.
A first interconnecting member 70 continuously connects the sun
gear member 22 of the planetary gear set 20 with the ring gear
member 34 of the planetary gear set 30 and the ring gear member 44
of the planetary gear set 40. A second interconnecting member 72
continuously connects the planet carrier assembly member 26 of the
planetary gear set 20 with the planet carrier assembly member 36 of
the planetary gear set 30 and the sun gear member 42 of the
planetary gear set 40.
A first torque-transmitting device, such as brake 80, selectively
connects the planet carrier assembly member 46 of the planetary
gear set 40 with the transmission housing 60. A second
torque-transmitting device, such as brake 82, selectively connects
the sun gear member 52 of the planetary gear set 50 with the
transmission housing 60. A third torque-transmitting device, such
as clutch 84, selectively connects the planet carrier assembly
member 26 of the planetary gear set 20, the planet carrier assembly
member 36 of the planetary gear set 30 and the sun gear member 42
of the planetary gear set 40 via interconnecting member 72 with the
ring gear member 54 of the planetary gear set 50. A fourth
torque-transmitting device, such as clutch 85, selectively connects
the sun gear member 22 of the planetary gear set 20, the ring gear
member 34 of the planetary gear set 30 and the ring gear member 44
of the planetary gear set 40 via interconnecting member 70 with the
sun gear member 52 of the planetary gear set 50. A fifth
torque-transmitting device, such as clutch 86, selectively connects
the sun gear member 22 of the planetary gear set 20, the ring gear
member 34 of the planetary gear set 30 and the ring gear member 44
of the planetary gear set 40 via interconnecting member 70 with the
planet carrier assembly member 56 of the planetary gear set 50. A
sixth torque-transmitting device, such as clutch 87, selectively
connects the sun gear member 32 of the planetary gear set 30 with
the ring gear member 54 of the planetary gear set 50.
As shown in FIG. 1b, and in particular the truth table disclosed
therein, the torque-transmitting devices are selectively engaged in
combinations of three to provide ten forward speed ratios and one
reverse speed ratio, all with single transition sequential shifts
and three overdrive ratios.
As set forth above, the engagement schedule for the
torque-transmitting devices is shown in the truth table of FIG. 1b.
The chart of FIG. 1b describes the ratio steps that are attained in
the above described transmission. For example, the step ratio
between the first and second forward speed ratios is 1.53, while
the step ratio between the reverse speed ratio and first forward
ratio is -0.70.
Referring to FIG. 1c, the embodiment of powertrain 10 depicted in
FIG. 1a is illustrated in a lever diagram format. A lever diagram
is a schematic representation of the components of a mechanical
device such as an automatic transmission. Each individual lever
represents a planetary gearset, wherein the three basic mechanical
components of the planetary gear are each represented by a node.
Therefore, a single lever contains three nodes: one for the sun
gear member, one for the planet gear carrier member, and one for
the ring gear member. The relative length between the nodes of each
lever can be used to represent the ring-to-sun ratio of each
respective gearset. These lever ratios, in turn, are used to vary
the gear ratios of the transmission in order to achieve appropriate
ratios and ratio progression. Mechanical couplings or
interconnections between the nodes of the various planetary gear
sets are illustrated by thin, horizontal lines and torque
transmitting devices such as clutches and brakes are presented as
interleaved fingers. If the device is a brake, one set of the
fingers is grounded. Further explanation of the format, purpose and
use of lever diagrams can be found in SAE Paper 810102, authored by
Benford, Howard and Leising, Maurice, "The Lever Analogy: A New
Tool in Transmission Analysis", 1981, which is hereby fully
incorporated by reference.
The powertrain 10 includes an input member 17 continuously
connected with the engine 12, an output member 19 continuously
connected with the final drive mechanism 16, a first planetary gear
set 20A having three nodes: a first node 22A, a second node 26A and
a third node 24A; a second planetary gear set 30A having three
nodes: a first node 32A, a second node 36A and a third node 34A; a
third planetary gear set 40A having three nodes: a first node 42A,
a second node 46A and a third node 44A; and a fourth planetary gear
set 50A having three nodes: a first node 52A, a second node 56A and
a third node 54A.
The input member 17 is continuously connected with the node 24A.
The output member 19 is continuously connected with the node
56A.
The node 22A is continuously connected with nodes 34A and 44A via
interconnecting member 70. The node 26A is continuously connected
with nodes 36A and 42A via interconnecting member 72.
A first torque-transmitting device, such as brake 80, selectively
connects the node 46A with the transmission housing 60. A second
torque-transmitting device, such as brake 82, selectively connects
the node 52A with the transmission housing 60. A third
torque-transmitting device, such as clutch 84, selectively connects
the nodes 26A, 36A and 42A via interconnecting member 72 with the
node 54A. A fourth torque-transmitting device, such as clutch 85,
selectively connects the nodes 22A, 34A and 44A via interconnecting
member 70 with the node 52A. A fifth torque-transmitting device,
such as clutch 86, selectively connects the nodes 22A, 34A and 44A
via interconnecting member 70 with the node 56A. A sixth
torque-transmitting device, such as clutch 87, selectively connects
the node 32A with the node 54A.
To establish ratios, three torque-transmitting devices are engaged
for each gear state. The engaged torque-transmitting devices are
represented by an "X" in each respective row of FIG. 1b. For
example, to establish reverse gear, the brakes 80, 82 and clutch 86
are engaged. The brake 80 engages the node 46A with the
transmission housing 60. The brake 82 engages the node 52A with the
transmission housing 60. The clutch 86 engages the nodes 22A, 34A
and 44A via interconnecting member 70 with the node 56A. Likewise,
the ten forward ratios are achieved through different combinations
of clutch engagement as per FIG. 1b.
The powertrain 10 (and powertrain 110 described below) may share
components with a hybrid vehicle, and such a combination may be
operable in a "charge-depleting mode". For purposes of the present
invention, a "charge-depleting mode" is a mode wherein the vehicle
is powered primarily by an electric motor/generator such that a
battery is depleted or nearly depleted when the vehicle reaches its
destination. In other words, during the charge-depleting mode, the
engine 12 is only operated to the extent necessary to ensure that
the battery is not depleted before the destination is reached. A
conventional hybrid vehicle operates in a "charge-sustaining mode",
wherein if the battery charge level drops below a predetermined
level (e.g., 25%) the engine is automatically run to recharge the
battery. Therefore, by operating in a charge-depleting mode, the
hybrid vehicle can conserve some or all of the fuel that would
otherwise be expended to maintain the 25% battery charge level in a
conventional hybrid vehicle. It should be appreciated that a hybrid
vehicle powertrain is preferably only operated in the
charge-depleting mode if the battery can be recharged after the
destination is reached by plugging it into an energy source.
DESCRIPTION OF A SECOND EXEMPLARY EMBODIMENT
In FIG. 2a a powertrain 110 is shown having a conventional engine
and torque converter 12, a planetary transmission 114, and a
conventional final drive mechanism 16. The engine 12 may be powered
using various types of fuel to improve the efficiency and fuel
economy of a particular application. Such fuels may include, for
example, gasoline; diesel; ethanol; dimethyl ether; etc.
The planetary transmission 114 includes an input member 17
continuously connected with the engine 12, a planetary gear
arrangement 118, and an output member 19 continuously connected
with the final drive mechanism 16. The planetary gear arrangement
118 includes four planetary gear sets 120, 130, 140 and 150.
The planetary gear set 120 includes a sun gear member 122, a ring
gear member 124, and a planet carrier assembly member 126. The
planet carrier assembly member 126 includes a plurality of pinion
gears 127 rotatably mounted on a carrier member 129 and disposed in
meshing relationship with both the sun gear member 122 and the ring
gear member 124.
The planetary gear set 130 includes a sun gear member 132, a ring
gear member 134, and a planet carrier assembly member 136. The
planet carrier assembly member 136 includes a plurality of pinion
gears 137 rotatably mounted on a carrier member 139 and disposed in
meshing relationship with both the sun gear members 132 and the
ring gear member 134.
The planetary gear set 140 includes a sun gear member 142, a ring
gear member 144, and a planet carrier assembly member 146. The
planet carrier assembly member 146 includes a plurality of pinion
gears 147 mounted on a carrier member 149 and disposed in meshing
relationship with both the ring gear member 144 and the sun gear
member 142.
The planetary gear set 150 includes a sun gear member 152, a ring
gear member 154, and a planet carrier assembly member 156. The
planet carrier assembly member 156 includes a plurality of pinion
gears 157 mounted on a carrier member 159 and disposed in meshing
relationship with both the ring gear member 154 and the sun gear
member 152.
The planetary gear arrangement also includes six
torque-transmitting devices 180, 182, 184, 185, 186 and 187. The
torque-transmitting devices 180, 182 and 184 are stationary-type
torque-transmitting devices, commonly termed brakes or reaction
clutches. The torque-transmitting devices 185, 186 and 187 are
rotating-type torque-transmitting devices, commonly termed
clutches.
The input member 17 is continuously connected with the ring gear
member 124 of the planetary gear set 120. The output member 19 is
continuously connected with the planet carrier assembly member 156
of the planetary gear set 150.
A first interconnecting member 170 continuously connects the sun
gear member 122 of the planetary gear set 120 with the planet
carrier assembly member 136 of the planetary gear set 130 and the
ring gear member 144 of the planetary gear set 140. A second
interconnecting member 172 continuously connects the planet carrier
assembly member 126 of the planetary gear set 120 with the sun gear
member 132 of the planetary gear set 130 and the planet carrier
assembly member 146 of the planetary gear set 140.
A first torque-transmitting device, such as brake 180, selectively
connects the sun gear member 122 of the planetary gear set 120, the
planet carrier assembly member 136 of the planetary gear set 130
and the ring gear member 144 of the planetary gear set 140 via
interconnecting member 170 with the transmission housing 160. A
second torque-transmitting device, such as brake 182, selectively
connects the ring gear member 154 of the planetary gear set 150
with the transmission housing 160. A third torque-transmitting
device, such as brake 184, selectively connects the sun gear member
152 with the transmission housing 160. A fourth torque-transmitting
device, such as clutch 185, selectively connects the planet carrier
assembly member 126 of the planetary gear set 120, the sun gear
member 132 of the planetary gear set 130 and the planet carrier
assembly member 146 of the planetary gear set via interconnecting
member 172 with the planet carrier assembly member 156 of the
planetary gear set 150. A fifth torque-transmitting device, such as
clutch 186, selectively connects the ring gear member 134 of the
planetary gear set 130 with the ring gear member 154 of the
planetary gear set 150. A sixth torque-transmitting device, such as
clutch 187, selectively connects the sun gear member 142 of the
planetary gear set 140 with the sun gear member 152 of the
planetary gear set 150.
As shown in FIG. 2b, and in particular the truth table disclosed
therein, the torque-transmitting devices are selectively engaged in
combinations of three to provide ten forward speed ratios and one
reverse speed ratio, all with single transition sequential shifts
and three overdrive ratios.
As set forth above, the engagement schedule for the
torque-transmitting devices is shown in the truth table of FIG. 2b.
The chart of FIG. 2b describes the ratio steps that are attained in
the above described transmission. For example, the step ratio
between the first and second forward speed ratios is 1.93, while
the step ratio between the reverse speed ratio and first forward
ratio is -0.80.
Referring to FIG. 2c, the embodiment of powertrain 110 depicted in
FIG. 2a is illustrated in a lever diagram format. The powertrain
110 includes an input member 17 continuously connected with the
engine 12, an output member 19 continuously connected with the
final drive mechanism 16, a first planetary gear set 120A having
three nodes: a first node 122A, a second node 126A and a third node
124A; a second planetary gear set 130A having three nodes: a first
node 132A, a second node 136A and a third node 134A; a third
planetary gear set 140A having three nodes: a first node 142A, a
second node 146A and a third node 144A; and a fourth planetary gear
set 150A having three nodes: a first node 152A, a second node 156A
and a third node 154A.
The input member 17 is continuously connected with the node 124A.
The output member 19 is continuously connected with the node
156A.
The node 122A is continuously connected with nodes 136A and 144A
via interconnecting member 170. The node 126A is continuously
connected with the nodes 132A and 146A via interconnecting member
172.
A first torque-transmitting device, such as brake 180, selectively
connects the nodes 122A, 136A and 144A via interconnecting member
170 with the transmission housing 160. A second torque-transmitting
device, such as brake 182, selectively connects the node 154A with
the transmission housing 160. A third torque-transmitting device,
such as brake 184, selectively connects the node 152A with the
transmission housing 160. A fourth torque-transmitting device, such
as clutch 185, selectively connects the nodes 126A, 132A and 146A
via interconnecting member 172 with the node 156A. A fifth
torque-transmitting device, such as clutch 186, selectively
connects the node 134A with the node 154A. A sixth
torque-transmitting device, such as clutch 187, selectively
connects the node 142A with the node 152A.
To establish ratios, three torque-transmitting devices are engaged
for each gear state. The engaged torque-transmitting devices are
represented by an "X" in each respective row of FIG. 2b. For
example, to establish reverse gear, the brakes 180, 184 and clutch
186 are engaged. The brake 180 engages the nodes 122A, 136A and
144A with the transmission housing 160. The brake 184 engages the
node 152A with the transmission housing 160. The clutch 186 engages
the node 134A with the node 154A. Likewise, the ten forward ratios
are achieved through different combinations of clutch engagement as
per FIG. 2b.
While the best modes for carrying out the invention have been
described in detail, those familiar with the art to which this
invention relates will recognize various alternative designs and
embodiments for practicing the invention within the scope of the
appended claims.
* * * * *